In order to use solar radiation as an energy source, solar cell arrays have been used to convert the solar radiation into electrical energy. Where solar radiation is to be used as an energy source for a satellite or the like, it is critical that the solar cell array and system for transferring power therefrom be efficient, reliable and low in weight due to the typically large loads and power requirements of the satellite. In order to accomplish the first two objectives, a continuous transfer of the maximum available power from the solar cell array is typically attempted.
One known system for transferring the maximum available power from a solar cell array employs an auxiliary or separate reference solar array from which measurements are taken so that power to the load from the main solar cell array is not interrupted. The open circuit voltage of the auxiliary solar cell array is measured in order to sense the maximum power point of the auxiliary array and to track the maximum power point of the main solar cell array, the power transfer system forcing the main solar cell array to operate close to the tracked point. One major limitation of this power transfer system is that the auxiliary solar cell array must experience the same environment, temperature etc., as the main solar cell array in order to accurately track the main array's maximum power point.
In other known systems, measurements taken from the solar cell array itself have been used to sense the maximum power point of the array. These systems employ tracking circuits or scanning techniques to monitor various parameters of the solar cell array while the array is loaded. Such parameters include the solar cell array voltage and current, the dynamic impedance of the solar cell array and changes in power and current of the array. The tracking circuits of such systems are typically complex, costly and unreliable.